| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26996: usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error |
| |
| When ncm function is working and then stop usb0 interface for link down, |
| eth_stop() is called. At this piont, accidentally if usb transport error |
| should happen in usb_ep_enable(), 'in_ep' and/or 'out_ep' may not be enabled. |
| |
| After that, ncm_disable() is called to disable for ncm unbind |
| but gether_disconnect() is never called since 'in_ep' is not enabled. |
| |
| As the result, ncm object is released in ncm unbind |
| but 'dev->port_usb' associated to 'ncm->port' is not NULL. |
| |
| And when ncm bind again to recover netdev, ncm object is reallocated |
| but usb0 interface is already associated to previous released ncm object. |
| |
| Therefore, once usb0 interface is up and eth_start_xmit() is called, |
| released ncm object is dereferrenced and it might cause use-after-free memory. |
| |
| [function unlink via configfs] |
| usb0: eth_stop dev->port_usb=ffffff9b179c3200 |
| --> error happens in usb_ep_enable(). |
| NCM: ncm_disable: ncm=ffffff9b179c3200 |
| --> no gether_disconnect() since ncm->port.in_ep->enabled is false. |
| NCM: ncm_unbind: ncm unbind ncm=ffffff9b179c3200 |
| NCM: ncm_free: ncm free ncm=ffffff9b179c3200 <-- released ncm |
| |
| [function link via configfs] |
| NCM: ncm_alloc: ncm alloc ncm=ffffff9ac4f8a000 |
| NCM: ncm_bind: ncm bind ncm=ffffff9ac4f8a000 |
| NCM: ncm_set_alt: ncm=ffffff9ac4f8a000 alt=0 |
| usb0: eth_open dev->port_usb=ffffff9b179c3200 <-- previous released ncm |
| usb0: eth_start dev->port_usb=ffffff9b179c3200 <-- |
| eth_start_xmit() |
| --> dev->wrap() |
| Unable to handle kernel paging request at virtual address dead00000000014f |
| |
| This patch addresses the issue by checking if 'ncm->netdev' is not NULL at |
| ncm_disable() to call gether_disconnect() to deassociate 'dev->port_usb'. |
| It's more reasonable to check 'ncm->netdev' to call gether_connect/disconnect |
| rather than check 'ncm->port.in_ep->enabled' since it might not be enabled |
| but the gether connection might be established. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26996 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.15.157 with commit 7f67c2020cb08499c400abf0fc32c65e4d9a09ca |
| Fixed in 6.1.88 with commit 0588bbbd718a8130b98c54518f1e0b569ce60a93 |
| Fixed in 6.6.29 with commit f356fd0cbd9c9cbd0854657a80d1608d0d732db3 |
| Fixed in 6.8.8 with commit 7250326cbb1f4f90391ac511a126b936cefb5bb7 |
| Fixed in 6.9 with commit 6334b8e4553cc69f51e383c9de545082213d785e |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-26996 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/usb/gadget/function/f_ncm.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/7f67c2020cb08499c400abf0fc32c65e4d9a09ca |
| https://git.kernel.org/stable/c/0588bbbd718a8130b98c54518f1e0b569ce60a93 |
| https://git.kernel.org/stable/c/f356fd0cbd9c9cbd0854657a80d1608d0d732db3 |
| https://git.kernel.org/stable/c/7250326cbb1f4f90391ac511a126b936cefb5bb7 |
| https://git.kernel.org/stable/c/6334b8e4553cc69f51e383c9de545082213d785e |
